Idler roller device for troughed conveyor belts

ABSTRACT

A pair of urethane idler rollers having center bearing holes with but one entrance journaled on, and enclosing the upper metal bearing portions of upwardly inclined shafts, each supported at one end. The shafts and rollers thereon extend upwardly and outwardly in opposite directions to engage the inclined sides of a troughed conveyor belt and skewed backwardly at a slight angle from a normal to its direction of movement. Movement of the troughed belt rotates and imposes a downward thrust on the skewed rollers to keep them from falling off, prevent the bearing surfaces from becoming exposed, and allow the belt to flex and shift relative to rollers without axially displacing the rollers.

United States Patent Speck Mar. 14, 1972 IDLER ROLLER DEVICE FORTROUGHED CONVEYOR BELTS Primary Examiner-Richard E. Aegerter AttorneySim& McBumey [57] ABSTRACT A pair of urethane idler rollers having centerbearing holes with but one entrance journaled on, and enclosing theupper metal bearing portions of upwardly inclined shafts, each supportedat one end. The shafts and rollers thereon extend upwardly and outwardlyin opposite directions to engage the inclined sides of a troughedconveyor belt and skewed backwardly at a slight angle from a normal toits direction of movement. Movement of the troughed belt rotates andimposes a downward thrust on the skewed rollers to keep them fromfalling off, prevent the bearing surfaces from becoming exposed, andallow the belt to flex and shift relative to rollers without axiallydisplacing the rollers.

10 Claims, 2 Drawing Figures PAIENTEUMARM m2 3,648,824

I N VEN 'IUR. CHARLES D. SPECK Agent IDLER ROLLER DEVICE FOR TROUGHEDCONVEYOR BELTS The invention relates to conveyors and particularly to anidler roller device for supporting troughed conveyor belts.

Existing troughed belt conveyor idlers on the market are relativelyexpensive and generally consist of three rollers precision antifrictionbearings, and seals which are difficult and expensive to maintain. In anabrasive environment they wear out quickly causing long shut downs, andrequire skilled personnel to service, repair or replace them.

The applicant has overcome the above problems by providing durableurethane rollers rotatably journaled on the upper free end portions of apair of inclined metal shafts. Urethane surfaces bearing against themetal shafts produce a low friction and long lasting device. In additionthe rollers can be, without removing the conveyor belt, quickly slippedon and off the inclined shaft when maintenance or replacement isrequired. The bearing surfaces are protected by the rollers which arearranged to prevent the belt from displacing them axially, and thelubricant injected between the bearing surfaces of the rollers and theshaftsFriction, heat, and wear are greatly reduced by axial thrustbearing means having substantially point contact with the shaft and theroller.

The applicant is aware of commercially available idler roller deviceshaving three quickly replaceable non-lubricating plastic conveyor rollswith short shouldered bearing shafts at opposite ends of each rollerrotatably mounted in half bearing slots in a plastic bracket or frame.However, the bearing surfaces of the shafts are only partially protectedfrom an abrasive or other destructive environments by the belt passingover them. The bearing shaft adjacent each side edge of the belt isfully exposed to the destructive environment. The device usuallyconsists of a horizontal center roller and inclined rollers at oppositesides of the center roller. Unlike the applicants two roller device thebelt cannot move freely axially along the rollers as a result of thebelt flexing and the uneven distribution of the material load placed onthe troughed conveyor belt.

An elongated generally flat support bracket is adapted to be centeredand fixed to the primary support or frame of a conveyor so that itextends transversely of the length and substantially horizontally underthe width of a troughed conveyor belt in a direction generally normal tothe direction of conveyance. A pair of roller support shafts are fixedlysupported at one end only to the bracket and project at a predeterminedangle upwardly, and outwardly in generally opposite directions from acentral portion of the bracket and skewed backwardly at a slight anglefrom the direction of movement of the conveyor belt. Each backwardlyinclined shaft is adapted to extend upwardly adjacent each upwardlyinclined side portion on opposite sides of troughed conveyor belt andhas a roller rotatably mounted on, over, protecting, and enclosing anupper end bearing portion of the shaft. The belt rotates the rollersabout the backwardly inclined axes, exerts a downward thrust, andprevents their being displaced axially. Each roller has a central holewith a single entrance thereto and into which each shaft extendsupwardly until its upper end is ad jacent to or contacts an upper topend wall of the roller. An axial thrust bearing is provided either bydirect engagement between the end shaft and the top wall of each rolleror preferably by a ball bearing interposed between them. The bearingsurfaces between the rollers and the shafts are preferably a urethanematerial engaging metal which extends the life of the bearing. Lubricantcan be introduced into the central hole before inserting the roller overthe shaft, or by providing a small hole or a grease fitting in the uppertop wall of the roller.

Therefore it is the primary object of the invention to provide aninexpensive, easily maintained, durable, self protecting idler rollerdevice for supporting a troughed conveyor belt.

FIG. 1 is a plan view of one idler roller device of the inventionmounted, under a troughed conveyor belt, on a primary conveyor supportshown in phantom lines; and

FIG. 2 is a partial cross sectional view in elevation of the idlerroller device taken approximately on line 2-2 of FIG. 1.

Referring to the drawings, a conveyor idler roller device or mechanism10 of the instant invention is shown, in full lines, centrally mountedon and extending between the opposite uprights or siderails R of aprimary conveyor support or frame C shown in phantom lines. In reality,a plurality of the idler roller devices 10 are fixed at intervals alongthe length of the conveyor support C and extend generally transverselythereto between an upper troughed feed run F and a lower return run notshown of a flexible endless conveyor belt B. The invention is concernedwith providing a simple, long lasting, economical, easily serviced, andreplaceable idler roller device for supporting and engaging thegenerally oppositely upwardly inclined side portions D, located onopposite sides of a central vertical plane P passing generally throughthe troughed belt midway between the opposite edges of the belt E andthe siderails R of the conveyor C.

The idler roller device 10 comprises support means, such as an elongatedsupport bracket or base plate 12 made preferably of conventional highstrength structural stock such as I, and T beams, U channels, L angleetc., having a high resistance to bending. As shown the support bracket12 extends longitudinally between the siderails R and rigidly fixed, bybolts and nuts N at its opposite end portions, to inwardly projectingsupport pads S, suitably fixed, as by welding, to the siderailsR..Altematively, the bracket 12 could be extended over and bolted orwelded to the rails R whereby it would become a cross support member ofthe primary conveyor support. The bracket 12 has a top wall 12aextending horizontally between the pads S and holes therein by which itis bolted to the pads S and a vertical wall 12b extending downwardlytherefrom. Opposite ends of the bracket 12 are open and into which thepads S project.

Fixed to a central portion of the top wall 12a are a pair of inclinedroller supports or bearing shafts 14 extending in generally oppositedirections from the central vertical plane P towards the siderails R,the edges e of the conveyor belt, and the opposite ends of the bracket12. Each support shaft 14 has a straight cylindrical bearing portion orsurface extending between an upper end or thrust bear-ing end surface14b and a lower end or portion 140 suitably fixed, as by welding to thecentral portion of the top wall 12a. The inclined shafts 14 projectupwardly and outwardly at an angle X from the top wall 12a andbackwardly, from the direction of movement of the troughed conveyor beltB, at a slight angle Y from a forward plane or forward side 120, of thebracket 12, normal to the direction of movement of the troughed belt Bindicated by the arrow.

The angle X of inclination between the axis of each shaft 14 and the topwall may vary in range between 5 and 70 but are preferably equallyinclined at substantially 45 as shown. Angles Y between the inclinedaxis of each shaft and a forward plane or the side 12c normal to themovement of the belt B may vary between l-l0 but situated preferablyequally inclined at substantially an angle of 5.

The shafts 14 can be made in any well known manner and are preferablyconstructed from round smooth cold rolled metal shafting of standarddiameters which requires substantially no machining to prepare thebearing surface. They can be straight instead of being bent at the lowerend portion 14c as shown. The lower ends of the shafts could be cut offflat at angle and welded to the top wall 12a whereby the shafts form agenerally V-shape configuration. In some instances such as, when anarrower belt is to be supported, the lower ends of the shafts could bewelded to a center post or shaft, to form a Y shaped structure, whichpost is then welded to the top wall 12a or other suitable support means.Certainly, the shafts can be extended and adapted to be fasteneddirectly to the primary conveyor support or fastened to the bracket 12in any suitable, conventional well known manner just as long as thedesired angular relationship is achieved and maintained.

A pair of idler rollers 20, are rotatably mounted on, over, and aboutthe upper bearing portions 14a of the shafts 14. Each roller 20 is ofgenerally cylindrical shape having a bottom surface or wall 20a, and endwall or top surface 20b, an outer annular wall or peripheral surface 20cextending between them, and a center bearing hole 20d with but oneentrance, at the bottom surface 20a at one end of the roller, for theshaft 14 to enter into. The center bearing hole extends along thecentral axis of the roller from the bottom surface 20a to an innerbearing surface or end wall 20e opposite the top surface 20b. Thebearing hole is made just slightly larger in diameter than the diameterof the bearing portion 14a, so as to provide a good bearing fit betweenthe roller and the portion 1411. As shown the roller 20, in thisinstance, has an annular chamber 20f situated between the outer wall 200and an inner annular wall or bearing surface 203 around the centerbearing hole 20d. When the rollers 20 are small, excess weight and costsare not as important, the rollers 20 may be made solid instead of hollowas shown. A lighter roller reduces the axial end thrust and wear betweenthe roller and its support shaft 14.

Various metals and plastic materials may be used for making the rollersand which provide a good wearing, long lasting, and durable bearingsurface in combination with the metal bearing portions 14a of the shafts14. In addition to bearing quality, the material of which the roller ismade must have good resistance to at least the environment in which itis being used. Preferably, the roller material used should be resistantto as many of the destructive substances which are known to exist inareas where conveyors of this type are used and thereby the rollerdevice could be used universally in any of those environments. It hasbeen found that urethane plastic material is highly resistant to manycorrosive and abrasive environments and provides a long lasting,durable, and low friction bearing when journaled for engagement with ametal shaft. Therefore, the rollers 20 could be made entirely ofurethane or of other materials with a urethane coating or liner ofpredetermined thickness on its exposed exterior surfaces and on theinner bearing surfaces 20g and 20e around the center hole 2011.Alternatively, the bearing portions 140 of shafts 14 could have aurethane coating or liner and engage either a metal roller or a urethaneroller with a metal coating or liner on the inner bearing surfaces 203and 20e. Preferably, the bearing between the bearing portion 14a and theinner bearing surface 20g is any suitable construction and combinationof materials which includes a smooth metal surface in engagement with asmooth urethane surface.

Thrust bearing means 30 are provided for simultaneously reducing thearea of frictional contact, wear, heat, and to resist the axial thrustbetween the shafts l4 and the rollers 20. Each of the thrust bearingmeans 30 comprises at least a member having a convex surface as ispreferably a metal spherical ball bearing 32 situated, in the centerhole 20d, between the upper end or thrust bearing surface 14b of shaft14 and the inner wall or thrust bearing surface 20e of the roller 20.The ball bearing 32 provides substantially point contact with each ofthe surfaces 14b and 20e, is smaller in diameter than the center hole,and is free to rotate within the center bearing hole, hence changing itspoints of contact and distributing the wear evenly over its peripheralsurface. Axial thrust bearing means of other suitable designs may beused. For example either or both the upper end surface 14b and the innerthrust bearing surface 20e could be of convex shape or have the shape ofa partial sphere. Thus you could either have point contact between apair of convex or partly spherical surfaces, or between a convex orpartly spherical surface and a substantially flat surface. Also, eitherone or both of the thrust bearing surfaces 140 and 20e could be aconcave surface of larger radius than the radius of the contactingconvex or partly spherical surface. In some instances where the diameterand hence the cross sectional area of the shaft 14 and the roller aresmall, the surfaces 14a and 20e which are shown as being generally flatcould be allowed to engage one another without generating too muchfriction, heat, and wear. However, in all cases, it is advisable toprovide lubricating grease or oil between the bearing surfaces. Thebearing surfaces can be lubricated by either coating them and packingthe upper end of center hole with a sufficient amount of grease beforeinserting the roller 20 onto the shafts 14. Another method is to providea small oil hole 20h preferably ofiset or slanted as shown from thecentral axis of rotation of the roller, through the top wall 20b andinto the center bearing hole 20d. As shown a grease gun fitting 40 isinserted into slanted hole and fixed at an angle to the end wall 20b ofthe roller in any suitable conventional manner, whereby lubricating oilor grease can be pumped under pressure into the center hole 20d and inbetween the bearing surfaces. Also, the center of gravity of the greasefilling is substantially at the central axis of rotation to helpmaintain the roller in balance.

A plurality of the roller devices 10 are suitably mounted at spacedintervals along the length of the conveyor C with the rollers 20 underand in supporting engagement with the undersides of the upwardlyinclined side portions D adjacent opposite sides E of the longitudinallyextending troughed feed run F of the conveyor belt B. The concavedcenter portion of the troughed belt B between the inclined sides and therollers, is unsupported and hence the belt B can move downwardly variousslight amounts depending upon the weight of the load placed thereon.However, the transverse distance between the rollers is such, as toallow approximately one-third or less of the width of the belt to extendbetween them and to accommodate a very small portion of the totalpossible load. Therefore a small load on the troughed belt between therollers would normally be of insufficient weight to move the beltdownward or out of engagement with the rollers. Upon loading the belt Bthe center of the trough fills quickly and then the added load extendingup the inclined sides counteracts the weight of the load in the centerof the trough. However, the belt B would most always be loaded unevenlywhich causes the side portions D of the belt to shift up and downrelative to the rollers 20.

As the troughed feed run F of the conveyor belt B moves between theloading and the dumping stations, it engages the skewed rollers 20 atthe slight relative angle Y backwardly away from the direction ofmovement of the belt. Belt B moving in the direction indicated by thearrow, simultaneously rotates and exerts a downward thrust to rollers20. The downward thrust is of sufficient magnitude to resist the upwardopposing force resulting from any upward movement of the side portions Dof the belt B along the axial length of the rollers. Therefore in normaloperation of the conveyor the rotating rollers are prevented fromfalling off the shafts l4, constantly maintained substantially in theextreme downward position, and prevents the bearing surfaces of portionsfrom becoming exposed to the environment which may be abrasive orcorrosive in nature. In addition the bearing surfaces 14a are furtherprotected by the lubricant which under gravity moves downwardly veryslowly and oozes out the bottom end of the rollers 20. The rate at whichthe lubricant moves downwardly depends, of course, on its viscosity andcohesiveness. High quality conventional lubricants of high viscosity,and good cohesive properties which are unaffected by a normal rise intemperature, such as fibrous wheel bearing grease, are preferred. Also,the exposed lubricant which may become contaminated at the bottom ofrollers 20 cannot be carried upwardly to the bearings surfaces.

Maintaining the durable idler roller device 10 in good running conditionis simple and economical. The rollers 20 can be inspected, lubricated,and serviced easily without removing the conveyor belt B or the idlerroller device 10 from the primaryconveyor support C. The conveyor belt Bis simply lifted out of engagement with the roller which can then beslipped on or off of the support shafts 14 for servicing, or replacementthereof.

It is to be understood that many modifications may be made of theembodiments of the invention disclosed hereinabove without departingfrom the spirit of the invention and which are within the scope of theappended claims.

What i claim as my invention is:

1. An idler roller device adapted to be supported by a primary conveyorsupport and to supportingly engage opposite upwardly inclined sideportions of a troughed conveyor belt, comprising:

means, fixed to the primary conveyor support, including a pair ofupwardly, outwardly and backwardly inclined support shafts eachsupported at one end from which the support shafts extend insubstantially opposite directions to opposite upper ends of the supportshafts for supporting a pair of rollers under and in supportingengagement with the said opposite upwardly inclined side portions of thebelt and for rotation by the belt about axes and bearing surfaces of thesupport shafts inclined both upwardly adjacent the inclined sideportions. and backwardly from a direction of movement of the troughedconveyor belt and a vertical plane normal to the direction of movement;and pair of idler rollers rotatably mounted on the upwardly andbackwardly inclined support shafts, each roller having a center bearinghole into which one of the inclined support shafts extends, a singleentrance into the center bearing hole, at one end of the roller, bywhich the roller is inserted over the upper end of one of the supportshafts, and an end wall at an opposite end of the roller enclosing theupper end of one of the support shafts; whereby the rollers rotatefreely about upwardly, outwardly and backwardly inclined axes, the beltrotates and contacts the rollers at an angle and thereby exerts adownward thrust to maintain the rollers on the support shaft, preventsthe rollers from being displaced axially during the movement of thetroughed conveyor belt and exposing the bearing surfaces of the shafts,and the rollers can be easily slipped on and off the bearing shafts forservicing.

2. An idler roller device according to claim 1 wherein the bearingshafts and the rollers have smooth bearing surfaces engaging oneanother, and one of the smooth bearing surfaces is a metal surfaceengaging a urethane surface.

3. An idler roller device according to claim 2 further comprising:

axial thrust bearing means, having at least one convex surface, betweenthe upper ends of the shafts and the end walls within the center bearingholes of rollers, for providing a substantially reduced area of contactfor reducing friction, heat, and wear between the shafts and thedownwardly thrusted rollers.

4. An idler roller device according to claim 3 wherein the axial thrustbearing means comprises:

spherical ball bearings in the center bearing holes between the endwalls and the upper ends of the bearing shafts.

5. An idler roller device according to claim 4 wherein the rollers aremade of urethane material and the bearing shafts are made of metal.

6. An idler roller device according to claim 5 further comprising:

lubricating means for introducing lubricant into the center bearingholes, to, and in between the bearing surfaces of the shafts and therollers.

7. An idler roller device according to claim 6 wherein the lubricatingmeans comprises:

a grease fitting fixed to the end wall of each of the rollers and asmall hole extending from the grease fitting through the end wall intothe center bearing hole with an exit end of the small hole offset fromthe central axis of the roller.

8. An idler roller device according to claim 7 wherein the means forsupporting a pair of rollers further comprises:

a support bracket adapted to be fixed to the primary conveyor support insubstantially a horizontal position under the troughed conveyor belt andto which the one end of each of the bearing shafts is fixed.

9. An idler roller according to claim 8 wherein the inclined bearingsshafts are backwardly inclined from the vertical plane at an angle of 1to 10.

10. An idler roller device according to claim 9 wherein the bearingshafts and the rollers are inclined upwardly at an angle of 5 to 70 froma horizontal plane.

1. An idler roller device adapted to be supported by a primary conveyorsupport and to supportingly engage opposite upwardly inclined sideportions of a troughed conveyor belt, comprising: means, fixed to theprimary conveyor support, including a pair of upwardly, outwardly andbackwardly inclined support shafts each supported at one end from whichthe support shafts extend in substantially opposite directions toopposite upper ends of the support shafts for supporting a pair ofrollers under and in supporting engagement with the said oppositeupwardly inclined side portions of the belt and for rotation by the beltabout axes and bearing surfaces of the support shafts inclined bothupwardly adjacent the inclined side portions and backwardly from adirection of movement of the troughed conveyor belt and a vertical planenormal to the direction of movement; and a pair of idler rollersrotatably mounted on the upwardly and backwardly inclined supportshafts, each roller having a center bearing hole into which one of theinclined support shafts extends, a single entrance into the centerbearing hole, at one end of the roller, by which the roller is insertedover the upper end of one of tHe support shafts, and an end wall at anopposite end of the roller enclosing the upper end of one of the supportshafts; whereby the rollers rotate freely about upwardly, outwardly andbackwardly inclined axes, the belt rotates and contacts the rollers atan angle and thereby exerts a downward thrust to maintain the rollers onthe support shaft, prevents the rollers from being displaced axiallyduring the movement of the troughed conveyor belt and exposing thebearing surfaces of the shafts, and the rollers can be easily slipped onand off the bearing shafts for servicing.
 2. An idler roller deviceaccording to claim 1 wherein the bearing shafts and the rollers havesmooth bearing surfaces engaging one another, and one of the smoothbearing surfaces is a metal surface engaging a urethane surface.
 3. Anidler roller device according to claim 2 further comprising: axialthrust bearing means, having at least one convex surface, between theupper ends of the shafts and the end walls within the center bearingholes of rollers, for providing a substantially reduced area of contactfor reducing friction, heat, and wear between the shafts and thedownwardly thrusted rollers.
 4. An idler roller device according toclaim 3 wherein the axial thrust bearing means comprises: spherical ballbearings in the center bearing holes between the end walls and the upperends of the bearing shafts.
 5. An idler roller device according to claim4 wherein the rollers are made of urethane material and the bearingshafts are made of metal.
 6. An idler roller device according to claim 5further comprising: lubricating means for introducing lubricant into thecenter bearing holes, to, and in between the bearing surfaces of theshafts and the rollers.
 7. An idler roller device according to claim 6wherein the lubricating means comprises: a grease fitting fixed to theend wall of each of the rollers and a small hole extending from thegrease fitting through the end wall into the center bearing hole with anexit end of the small hole offset from the central axis of the roller.8. An idler roller device according to claim 7 wherein the means forsupporting a pair of rollers further comprises: a support bracketadapted to be fixed to the primary conveyor support in substantially ahorizontal position under the troughed conveyor belt and to which theone end of each of the bearing shafts is fixed.
 9. An idler rolleraccording to claim 8 wherein the inclined bearings shafts are backwardlyinclined from the vertical plane at an angle of 1* to 10*.
 10. An idlerroller device according to claim 9 wherein the bearing shafts and therollers are inclined upwardly at an angle of 5* to 70* from a horizontalplane.